FIG. 1 is a view schematically illustrating a fuel delivery system for a motor vehicle.
Referring to FIG. 1, the fuel delivery system for a motor vehicle delivers a fuel from a fuel tank 10 to a fuel supply line 30 using a fuel pump 20, and supplies the fuel delivered to the fuel supply line 30 to each injector 50 of an engine at constant pressure and flow rate using a pressure regulator 40. Further, the fuel delivery system for a motor vehicle returns the remaining fuel after being supplied to each injector 50 of the engine from the fuel supply line 30 to the fuel tank 10 through a fuel return line 60.
The above-mentioned fuel delivery system for a motor vehicle uses a general direct current (DC) motor as the fuel pump 20. By using the DC motor as the fuel pump, the fuel pump 20 of the fuel delivery system is rotated at a designed speed to deliver the fuel having the same or varying flow rate and pressure to the fuel supply line 30.
FIG. 2 illustrates an exploded perspective view of a brushless direct current (BLDC) motor 100 of a fuel delivery system for a motor vehicle according to the related art. The general BLDC motor 100 used as the fuel pump of the fuel delivery system for a motor vehicle according to the related art includes a cylindrical outer case 110, a stator 120 inserted into the outer case 110, a rotor 130 rotatably inserted into the stator 120, a shaft 135 guiding a rotation of the rotor 130, a pump outlet 140 closing one side of the outer case 110 and including a terminal 145, and a lower-side case 150 closing the other side of the outer case 110 and including an impeller 155 rotated by the rotation of the rotor 130.
The shaft 135 of the BLDC motor 100 according to the related art as described above has an end of one side which is rotatably coupled to the pump outlet 140, and an end of the other side which is rotatably coupled to the lower-side case 150. In particular, one side of the shaft 135 is extended by a significant length in one side direction from one side of the rotor 130 so as to be connected to the pump outlet 140. Accordingly, as a length of the shaft 135 is formed to be long, a support point is apart from the center of gravity of the rotor 130, which causes noise and vibration to be increased.